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FEMS Yeast Research Jun 2009The biochemical characterization of sugar uptake in yeasts started five decades ago and led to the early production of abundant kinetic and mechanistic data. However,... (Review)
Review
The biochemical characterization of sugar uptake in yeasts started five decades ago and led to the early production of abundant kinetic and mechanistic data. However, the first accurate overview of the underlying sugar transporter genes was obtained relatively late, due mainly to the genetic complexity of hexose uptake in the model yeast Saccharomyces cerevisiae. The genomic era generated in turn a massive amount of information, allowing the identification of a multitude of putative sugar transporter and sensor-encoding genes in yeast genomes, many of which are phylogenetically related. This review aims to briefly summarize our current knowledge on the biochemical and molecular features of the transporters of hexoses and pentoses in yeasts, when possible establishing links between previous kinetic studies and genomic data currently available. Emphasis is given to recent developments concerning the identification of d-xylose and l-arabinose transporter genes, which are thought to be key players in the optimization of S. cerevisiae strains for bioethanol production from lignocellulose hydrolysates.
Topics: Ascomycota; Biological Transport; Hexoses; Membrane Transport Proteins; Pentoses
PubMed: 19459982
DOI: 10.1111/j.1567-1364.2009.00509.x -
The Journal of Biological Chemistry Mar 1961
Topics: Carbohydrate Metabolism; Oxidation-Reduction; Pentoses; Pseudomonas; Pseudomonas fragi
PubMed: 13783864
DOI: No ID Found -
PloS One 2016The efficient use of hemicellulose in the plant cell wall is critical for the economic conversion of plant biomass to renewable fuels and chemicals. Previously, the...
The efficient use of hemicellulose in the plant cell wall is critical for the economic conversion of plant biomass to renewable fuels and chemicals. Previously, the yeast Saccharomyces cerevisiae has been engineered to convert the hemicellulose-derived pentose sugars xylose and arabinose to d-xylulose-5-phosphate for conversion via the pentose phosphate pathway (PPP). However, efficient pentose utilization requires PPP optimization and may interfere with its roles in NADPH and pentose production. Here, we developed an alternative xylose utilization pathway that largely bypasses the PPP. In the new pathway, d-xylulose is converted to d-xylulose-1-phosphate, a novel metabolite to S. cerevisiae, which is then cleaved to glycolaldehyde and dihydroxyacetone phosphate. This synthetic pathway served as a platform for the biosynthesis of ethanol and ethylene glycol. The use of d-xylulose-1-phosphate as an entry point for xylose metabolism opens the way for optimizing chemical conversion of pentose sugars in S. cerevisiae in a modular fashion.
Topics: Fermentation; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Fungal; Metabolic Networks and Pathways; Mutation; Pentose Phosphate Pathway; Pentoses; Phosphotransferases (Alcohol Group Acceptor); Saccharomyces cerevisiae; Xylose
PubMed: 27336308
DOI: 10.1371/journal.pone.0158111 -
Microbial Cell Factories Aug 2023Efficient conversion of pentose sugars remains a significant barrier to the replacement of petroleum-derived chemicals with plant biomass-derived bioproducts. While the...
Efficient conversion of pentose sugars remains a significant barrier to the replacement of petroleum-derived chemicals with plant biomass-derived bioproducts. While the oleaginous yeast Rhodosporidium toruloides (also known as Rhodotorula toruloides) has a relatively robust native metabolism of pentose sugars compared to other wild yeasts, faster assimilation of those sugars will be required for industrial utilization of pentoses. To increase the rate of pentose assimilation in R. toruloides, we leveraged previously reported high-throughput fitness data to identify potential regulators of pentose catabolism. Two genes were selected for further investigation, a putative transcription factor (RTO4_12978, Pnt1) and a homolog of a glucose transceptor involved in carbon catabolite repression (RTO4_11990). Overexpression of Pnt1 increased the specific growth rate approximately twofold early in cultures on xylose and increased the maximum specific growth by 18% while decreasing accumulation of arabitol and xylitol in fast-growing cultures. Improved growth dynamics on xylose translated to a 120% increase in the overall rate of xylose conversion to fatty alcohols in batch culture. Proteomic analysis confirmed that Pnt1 is a major regulator of pentose catabolism in R. toruloides. Deletion of RTO4_11990 increased the growth rate on xylose, but did not relieve carbon catabolite repression in the presence of glucose. Carbon catabolite repression signaling networks remain poorly characterized in R. toruloides and likely comprise a different set of proteins than those mainly characterized in ascomycete fungi.
Topics: Xylose; Proteomics; Pentoses; Glucose
PubMed: 37537586
DOI: 10.1186/s12934-023-02148-5 -
International Journal of Food Sciences... Mar 2014Xylitol, a five-carbon polyalcohol, holds a substantial place in the cure and prevention of a number of diseases. The foremost reason for its lesser usage in day-to-day... (Review)
Review
Xylitol, a five-carbon polyalcohol, holds a substantial place in the cure and prevention of a number of diseases. The foremost reason for its lesser usage in day-to-day practice is its cost. The method employed on large scale production of this polyol, i.e. chemical reduction, uses extensive machinery and expensive chemicals thus increasing the basic cost of the sugar. Yield of xylitol by other methods including fermentation and enzymatic production is far less than chemical reduction. We did a literature analysis and briefed out the various experiments carried out till date and concluded on the required studies for improving its production and lowering down its cost.
Topics: Aldehyde Reductase; Genetic Engineering; Humans; Microbiological Phenomena; Pentoses; Xylitol
PubMed: 24160912
DOI: 10.3109/09637486.2013.845651 -
Organic & Biomolecular Chemistry Oct 2017One of the possible synthetic routes to pentoses is the formose reaction pathway from C1 and C2 carbon sources, but preferential ribose generation in a one-pot reaction...
One of the possible synthetic routes to pentoses is the formose reaction pathway from C1 and C2 carbon sources, but preferential ribose generation in a one-pot reaction without any control of conditions has not been reported. We have tested a one-pot pentose formation and analyzed the products and mechanism in the reaction, using H-NMR and mass spectrometry. Hydroxyapatite (HAp), which consists of phosphate and calcium ions, worked continuously for cross-aldol reactions and Lobry de Bruyn-van Ekenstein transformations to yield ribose from formaldehyde and glycolaldehyde. The continuous reaction proceeds in one pot in hot water only in the presence of a HAp catalyst, without any fine pH control or any complicated condition control at each reaction step. Ribose production by HAp may be a reason why a pentose backbone was incorporated into nucleic acids in the prebiotic world.
Topics: Catalysis; Durapatite; Molecular Structure; Pentoses
PubMed: 28952648
DOI: 10.1039/c7ob02051a -
Organic Letters May 2019This work characterizes a previously undetected epimerization in the preparation of alkynyl diols from pentose precursors utilizing the Ohira-Bestmann reagent. Lithium...
This work characterizes a previously undetected epimerization in the preparation of alkynyl diols from pentose precursors utilizing the Ohira-Bestmann reagent. Lithium trimethylsilyldiazomethane (Colvin reagent) additions to the d-ribose and d-lyxose-derived benzylidene acetals provide the respective alkynyl diol stereoisomers, without epimerization. Regioselective tungsten-catalyzed cycloisomerizations of the d-ribose- and d-lyxose-derived alkynyl diols yield rigid bicyclic pyranose glycals, confirming the stereochemical fidelity of the Colvin alkynylation process.
Topics: Acetals; Alcohols; Alkynes; Catalysis; Ethers, Cyclic; Lithium Compounds; Molecular Structure; Pentoses; Ribose; Stereoisomerism; Tungsten
PubMed: 31013112
DOI: 10.1021/acs.orglett.9b01024 -
Journal of Bacteriology Jun 1963Dobrogosz, Walter J. (University of Illinois, Urbana) and Ralph D. DeMoss. Pentose utilization by Pediococcus pentosaceus. J. Bacteriol. 85:1356-1364. 1963.-Data are...
Dobrogosz, Walter J. (University of Illinois, Urbana) and Ralph D. DeMoss. Pentose utilization by Pediococcus pentosaceus. J. Bacteriol. 85:1356-1364. 1963.-Data are presented which indicate that pentoses are metabolized by Pediococcus pentosaceus through the use of an inducible phosphoketolase pathway. The utilization of each of the pentoses (l-arabinose, d-ribose, and d-xylose) appears to involve a different regulatory process. Thus, d-ribose was fermented by cells grown on any pentose or glucose, although growth on a pentose resulted in an increased ribose-fermenting capacity. l-Arabinose fermentation was only observed when cultures were grown in the presence of this pentose. Similarly, d-xylose fermentation was a specific response to the presence of xylose in the growth medium. In this case, however, growth occurred only at a very low rate unless another readily utilizable substrate (in low concentration) was added to the growth medium. Under these conditions, an aerobic atmosphere was more stimulatory than anaerobiosis for induction and growth on xylose. The possible cryptic nature of xylose utilization in this organism is described.
Topics: Aldehyde-Lyases; Anaerobiosis; Arabinose; Carbohydrate Metabolism; Culture Media; Fermentation; Glucose; Isomerases; NAD; Pediococcus; Pentoses; Phosphotransferases; Research; Ribose; Xylose
PubMed: 14047230
DOI: 10.1128/jb.85.6.1356-1364.1963 -
The Biochemical Journal Feb 19721. Rates of insulin release, glucose utilization (measured as [(3)H]water formation from [5-(3)H]glucose) and glucose oxidation (measured as (14)CO(2) formation from...
1. Rates of insulin release, glucose utilization (measured as [(3)H]water formation from [5-(3)H]glucose) and glucose oxidation (measured as (14)CO(2) formation from [1-(14)C]- or [6-(14)C]-glucose) were determined in mouse pancreatic islets incubated in vitro, and were used to estimate the rate of oxidation of glucose by the pentose cycle pathway under various conditions. Rates of oxidation of [U-(14)C]ribose and [U-(14)C]xylitol were also measured. 2. Insulin secretion was stimulated fivefold when the medium glucose concentration was raised from 3.3 to 16.7mm in the absence of caffeine; in the presence of caffeine (5mm) a similar increase in glucose concentration evoked a much larger (30-fold) increase in insulin release. Glucose utilization was also increased severalfold as the intracellular glucose concentration was raised over this range, particularly between 5 and 11mm, but the rate of oxidation of glucose via the pentose cycle was not increased. 3. Glucosamine (20mm) inhibited glucose-stimulated insulin release and glucose utilization but not glucose metabolism via the pentose cycle. No evidence was obtained for any selective effect on the metabolism of glucose via the pentose cycle of tolbutamide, glibenclamide, dibutyryl 3':5'-cyclic AMP, glucagon, caffeine, theophylline, ouabain, adrenaline, colchicine, mannoheptulose or iodoacetamide. Phenazine methosulphate (5mum) increased pentose-cycle flux but inhibited glucose-stimulated insulin release. 4. No formation of (14)CO(2) from [U-(14)C]ribose could be detected: [U-(14)C]xylitol gave rise to small amounts of (14)CO(2). Ribose and xylitol had no effect on the rate of oxidation of glucose; ribitol and xylitol had no effect on the rate of glucose utilization. Ribose, ribitol and xylitol did not stimulate insulin release under conditions in which glucose produced a large stimulation. 5. It is concluded that in normal mouse islets glucose metabolism via the pentose cycle does not play a primary role in insulin-secretory responses.
Topics: Animals; Carbon Dioxide; Carbon Isotopes; Glucose; In Vitro Techniques; Insulin; Insulin Secretion; Islets of Langerhans; Mice; Oxidation-Reduction; Pentoses; Phenazines; Ribose; Secretory Rate; Tritium; Xylitol
PubMed: 4561619
DOI: 10.1042/bj1260525 -
Glycobiology May 2016Apiose is a unique branched-chain pentose found principally in plants. It is a key component of structurally complex cell wall polysaccharides, as well as being present... (Review)
Review
Apiose is a unique branched-chain pentose found principally in plants. It is a key component of structurally complex cell wall polysaccharides, as well as being present in a large number of naturally occurring secondary metabolites. This review provides a comprehensive overview of the current state of knowledge on the metabolism and natural occurrence of apiose, using cyanogenic glycosides and their related compounds as a case study. The biological function of apiose and of apiosylated compounds is discussed.
Topics: Cell Wall; Pentoses; Plants
PubMed: 26848180
DOI: 10.1093/glycob/cww012